+

US9976923B2 - Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method - Google Patents

Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method Download PDF

Info

Publication number
US9976923B2
US9976923B2 US15/104,008 US201415104008A US9976923B2 US 9976923 B2 US9976923 B2 US 9976923B2 US 201415104008 A US201415104008 A US 201415104008A US 9976923 B2 US9976923 B2 US 9976923B2
Authority
US
United States
Prior art keywords
membrane
electrode
temperature
measurement
pressure
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active, expires
Application number
US15/104,008
Other versions
US20160320256A1 (en
Inventor
Martin Burgard
Drewes Ulfert
Nils Ponath
Andreas Rossberg
Thomas Uehlin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Endress and Hauser SE and Co KG
Original Assignee
Endress and Hauser SE and Co KG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Endress and Hauser SE and Co KG filed Critical Endress and Hauser SE and Co KG
Assigned to ENDRESS + HAUSER GMBH + CO. KG reassignment ENDRESS + HAUSER GMBH + CO. KG ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: BURGARD, Martin, DREWES, ULFERT, PONATH, NILS, ROSSBERG, ANDREAS, UEHLIN, THOMAS
Publication of US20160320256A1 publication Critical patent/US20160320256A1/en
Application granted granted Critical
Publication of US9976923B2 publication Critical patent/US9976923B2/en
Assigned to ENDRESS+HAUSER SE+CO.KG reassignment ENDRESS+HAUSER SE+CO.KG CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: ENDRESS+HAUSER GMBH+CO. KG
Active legal-status Critical Current
Adjusted expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor
    • G01L9/125—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor with temperature compensating means
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/0041—Transmitting or indicating the displacement of flexible diaphragms
    • G01L9/0072—Transmitting or indicating the displacement of flexible diaphragms using variations in capacitance
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L9/00—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means
    • G01L9/12—Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means by making use of variations in capacitance, i.e. electric circuits therefor

Definitions

  • the present invention relates to a capacitive pressure-measuring cell having a counter body, a measurement membrane that is connected to the counter body and is deformable by a pressure to be measured, and at least one temperature sensor.
  • Temperature sensors are often integrated in pressure-measuring cells, in order to compensate for the static temperature error.
  • this temperature sensor is typically arranged on the rear face of the ceramic; it can, however, also be contained inside a connected evaluation electronic device. If a pressure-measuring cell is in thermal equilibrium with its surroundings, the temperature dependence of the pressure measurement can be well compensated for by means of such a temperature sensor and a suitable processing of the measurement signal. However, temperature jumps can lead to significant measuring errors, which can hardly be compensated for using known methods.
  • the temperature of the measurement membrane quickly follows the temperature of the medium the membrane is exposed to, whereas the heat transfer between the rear face of the counter body and the measurement membrane occurs very slowly, namely, via a circumferential joint between counter body and joint on the outer edge of the measurement membrane and then through the volume of the counter body to its rear face.
  • a temperature measurement at the rear face of the counter body is always delayed.
  • the published German patent application DE 100 44 078 A1 discloses a pressure-measuring cell with two temperature sensors that are to be arranged at a distance in the direction of the expected temperature gradient.
  • the first temperature sensor is arranged at the measurement membrane that forms the front face of the pressure-measuring cell, where it can quickly follow the temperature changes of the medium
  • the second temperature sensor is arranged at the rear face of the counter body of the pressure measuring cell and facing away from the measurement membrane.
  • the first temperature sensor is arranged at the front face of the counter body, embedded in the joint and contacted via electrical transits through the base body.
  • thermosensor A comparison between the temperature signals of both temperature sensors then enables the detection of a temperature gradient and a more accurate compensation of the effects that are caused by the temperature gradient, such as a curvature of the measurement membrane and/or the counter body, or changes in rigidities.
  • the temperature gradient can be established using the time derivative of the signal from the first temperature sensor.
  • the joint between the measurement membrane and the counter body actually provides a significant thermal resistance, so that an additional temperature sensor at the front face of the counter body is, on the one hand, a significant improvement with regard to prior art; on the other hand, this temperature sensor is also exposed to the thermal influence of the counter body volume, so that, in case of quick temperature jumps, distortion is still to be expected. If a sealing ring is impacting the front face of the measurement membrane in the area of the joint, this can also have an influence on the temperature measurement value of the first temperature sensor, which can impair the temperature compensation.
  • the present invention is based upon the objective of providing a pressure-measuring cell and a method for operating it, wherein the pressure measuring cell provides a further improved temperature compensation.
  • the objective is achieved by the invention through the pressure measurement cell and the method.
  • the pressure sensor comprises an operating circuit; and a pressure-measuring cell comprising a counter body; a measurement membrane, which is arranged on the counter body and can be deformed by a pressure to be measured; and a capacitive transducer, which has at least one membrane electrode arranged at the measurement membrane and at least one counter-body electrode arranged at the counter body, wherein the capacitance between the membrane electrode and the counter-body electrode depends upon a pressure-dependent deformation of the measurement membrane, wherein at least the membrane electrode has a temperature-dependent impedance; wherein the operating circuit is designed to sense at least one capacitance between the at least one counter-body electrode and the at least one membrane electrode and to provide a pressure measurement value on the basis of at least one capacitance and to determine the impedance of the membrane electrode—particularly, the ohmic portion of the impedance of the membrane electrode.
  • the temperature dependence of the impedance is, in particular, provided by a temperature-dependent ohmic resistance of the membrane electrode material.
  • the operating circuit is designed to determine a temperature value for the measurement membrane, depending upon the impedance of the membrane electrode.
  • the operating circuit is designed, depending upon the impedance of the membrane electrode, to perform a temperature compensation and/or temperature gradient compensation, in order to provide a compensated pressure measurement value.
  • the pressure sensor according to the invention enables the determination of the measurement membrane temperature, which is generally influenced by the entire surface of the measurement membrane, and not only by the edge region, in which the measurement membrane is coupled with other heat sources or heat sinks, which distort the temperature measurement, thus providing an insufficient basis for a temperature compensation.
  • the pressure sensor according to the invention does not require any additional connections or transits through the counter body for determining the temperature of the measurement membrane.
  • the determination of the membrane temperature is cost-neutral as far as the design is concerned.
  • the operating circuit is designed to determine the impedance of the membrane electrode using a time constant of a charge and/or discharge process of the capacitance between the membrane electrode and the at least one counter body electrode.
  • the operating circuit along with the capacitance between the membrane electrode and the at least one counter body electrode, forms an oscillating circuit, wherein the operating circuit is designed to determine the impedance of the membrane electrode using a characteristic value of the oscillating circuit, e.g., a phase angle between a charging voltage and a charging current in the oscillating circuit, or using the quality or the damping of the oscillating circuit.
  • a characteristic value of the oscillating circuit e.g., a phase angle between a charging voltage and a charging current in the oscillating circuit, or using the quality or the damping of the oscillating circuit.
  • the impedance of the membrane electrode depends not only upon the temperature but also upon a deformation of the measurement membrane
  • the operating circuit is designed, depending upon the at least one capacitance between the membrane electrode and the at least one counter body electrode, to determine the deformation influence upon the impedance of the membrane electrode, and to compensate for it during the determination of a temperature value of the measurement membrane, wherein the temperature value determined in this way is to be used for performing a temperature compensation and/or temperature gradient compensation during the determination of the pressure measurement value.
  • the membrane electrode features a semiconductor—in particular, a metal oxide—especially, titanium dioxide.
  • the pressure sensor further comprises a second temperature sensor, which is arranged on a rear face of the counter body facing away from the measurement membrane, wherein the operating circuit is designed to perform a temperature compensation or a temperature gradient compensation depending upon a temperature of the measurement membrane determined by way of the impedance of the measurement membrane and using a temperature measurement value of the second temperature sensor.
  • the measurement membrane is joined with the counter body by way of a circumferential electroconductive joint in a pressure-tight manner, wherein the joint comprises, in particular, an active hard solder, and wherein the membrane electrode is connected to the joint in an electroconductive manner.
  • the capacitive transducer has a differential capacitor with a first counter body electrode and a second counter body electrode, wherein the first counter body electrode is surrounded by the second counter body electrode in a circular manner, and wherein the first capacitance between the first counter body electrode and the membrane electrode equals a second capacitance between the second counter body electrode and the membrane electrode, when the measurement membrane and the counter body are in their rest positions.
  • the method according to the invention for determining a pressure measurement value by means of a pressure sensor, which pressure sensor has a capacitive transducer for converting a pressure-dependent deformation of a measurement membrane into an electrical signal, wherein the pressure sensor comprises cross-sensitivities regarding the temperature of the measurement membrane and/or regarding the temperature gradient between the measurement membrane and further components of the pressure sensor, wherein the capacitive transducer has a membrane electrode with a temperature-dependent impedance, is a method that comprises the following steps: Determining a deformation-dependent capacitance measurement value of the capacitive transducer; determining a temperature-dependent impedance measurement value of the membrane electrode; and determining a temperature-compensated and/or temperature gradient-compensated pressure measurement value dependent upon the capacitance measurement value and the impedance measurement value.
  • FIG. 1 a longitudinal view through an exemplary embodiment of a pressure-measuring cell according to the invention.
  • FIG. 2 a diagram that depicts the loss angle tan (delta) as a function at various temperatures of the pressure
  • FIG. 3 a diagram that depicts discharge curves of a capacitor at various electrode temperatures.
  • the pressure-measuring cell 1 shown in FIG. 1 comprises a disk-shaped, ceramic measurement membrane 2 that is in a pressure-tight connection along a circumferential joint 4 with a much stiffer disk-shaped ceramic counter body 3 , thus creating a measuring chamber 5 between the counter body 3 and the measurement membrane 2 .
  • the measurement membrane and the counter body may comprise, in particular, corundum.
  • the joint may comprise, in particular, an active hard solder, for example, a Zr—Ni—Ti active hard solder.
  • the measuring membrane 2 has a membrane electrode 7 across its entire counter body surface that includes a metal oxide—especially, a doped metal oxide—for example, titanium dioxide doped with Nb or W, wherein the electrode has a diameter of 2 R, with R being the radius of the flexible area of the measuring diaphragm that corresponds to the internal radius of the joint.
  • a central, disk-shaped measuring electrode 8 is arranged that is contacted by a disk-shaped reference electrode 9 which is mainly of the same capacity as the diaphragm electrode 7 in the rest position of the measurement membrane 2 .
  • the distance of the reference electrode 9 to the measuring electrode 8 and the joint 4 is about 0.1 R each.
  • the reference electrode 9 and the measuring electrode 8 are in electrical contact via metallic transits 10 , 11 through the base body.
  • the membrane electrode 7 may, for example, be placed on switching ground via the joint.
  • the capacitances between the measurement electrode 8 and the membrane electrode 7 , on the one hand, and the reference electrode 9 and the membrane electrode 7 , on the other hand, are captured.
  • the determination of a pressure measurement value by means of these capacitances is generally known, and described in, for example, the published German patent application, DE 10 2011 078 557 A1.
  • the electrode material of the membrane electrode 7 has a temperature-dependent resistance, which provides the opportunity for determining the temperature of the measurement membrane 2 , and, based upon that, for performing a temperature compensation or a temperature gradient compensation. For this, different approaches are described below.
  • the capacitances between the counter body electrode and the membrane electrode of the pressure-measuring cell can be viewed as capacitances of an oscillating circuit, wherein the ohmic resistances in such an oscillating circuit can be determined by the tangent of the loss angle tan ( ⁇ ), wherein the loss angle ⁇ corresponds to the difference between 90° and the phase angle ⁇ between current and voltage.
  • the determining ohmic resistance is provided by the membrane electrode 7 and ranges over a typical operating temperature range, depending upon doping, between, for example, 1 and 8 k ⁇ . As shown in FIG.
  • the values for the tangent of the loss angle show a readily measurable temperature dependence, so that, after a determination of the loss angle, whose pressure-dependence still has to be corrected by means of the measured capacitances, the temperature of the measurement membrane 2 can be determined to a sufficiently accurate degree, as to therewith enable a temperature compensation to be performed.
  • an oscillating circuit which contains the measuring capacitance, needs to be operated preferably at its resonance frequency, which resonance frequency can, for example, be determined by means of a frequency sweep with a given excitation voltage.
  • capacitive pressure-measuring cells are often operated by charging pumps or so-called switched capacitor circuits, wherein, for example, a precision capacitor, whose capacitance is to be determined, is charged with a defined voltage, wherein the precision capacitor is subsequently discharged into an evaluation capacitor, wherein the resulting voltage of the evaluation capacitor is a measure for the sought capacitance.
  • switched capacitor circuits wherein, for example, a precision capacitor, whose capacitance is to be determined, is charged with a defined voltage, wherein the precision capacitor is subsequently discharged into an evaluation capacitor, wherein the resulting voltage of the evaluation capacitor is a measure for the sought capacitance.
  • the temperature-dependent resistance of the membrane electrode also has an influence on the discharge time of a capacitor, which contains the membrane electrode.
  • This provides the opportunity, by means of a sequence of charging and discharging processes—during which the capacitances of the membrane electrode are respectively charged and discharged over different times t 1 , t 2 , and t 3 —to determine a time constant and by said time constant to determine a temperature value for the measurement membranes. Based upon this, a temperature compensation or a temperature gradient compensation during the determination of a pressure measurement value can be performed.
  • a temperature compensation on the one hand, only one temperature value for the measurement membrane temperature can be used, which value is determined using the method described above, while, on the other hand, a second temperature sensor (not shown in FIG. 1 ) can additionally be used, which temperature sensor is arranged on the rear face of the counter body of the pressure-measuring cell.
  • a second temperature sensor not shown in FIG. 1
  • an additional temperature gradient compensation is possible.
  • a significant indication for a temperature gradient can also be obtained from the time derivative of the temperature of the measurement membranes.
  • the operating circuit can, in particular, be realized in the form of an ASIC, which is arranged on the rear face of the pressure-measuring cell. Furthermore, such an ASIC can also be only a partial component of the operating circuit, which ASIC, in particular, communicates with a main processor, which analyses the signals provided by the ASIC for performing a temperature compensation or temperature gradient compensation during determination of a pressure measurement value.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measuring Fluid Pressure (AREA)

Abstract

A pressure sensor comprises an operating circuit and a pressure-measuring cell comprising a counter body, a measurement membrane, which is arranged on the counter body and can be deformed by a pressure to be measured, and a capacitive transducer, which has at least one membrane electrode arranged on the measurement membrane and at least one counter-body electrode arranged on the counter body. The capacitance between the membrane electrode and the counter-body electrode depends on a pressure-dependent deformation of the measurement membrane, wherein at least the membrane electrode has a temperature-dependent impedance. The operating circuit is designed to sense at least one capacitance between the at least one counter-body electrode and the at least one membrane electrode and to provide a pressure measurement value on the basis of at least one capacitance and to determine the impedance of the membrane electrode—particularly, the ohmic portion of the impedance of the membrane electrode.

Description

TECHNICAL FIELD
The present invention relates to a capacitive pressure-measuring cell having a counter body, a measurement membrane that is connected to the counter body and is deformable by a pressure to be measured, and at least one temperature sensor.
BACKGROUND DISCUSSION
Temperature sensors are often integrated in pressure-measuring cells, in order to compensate for the static temperature error. In generic pressure-measuring cells, this temperature sensor is typically arranged on the rear face of the ceramic; it can, however, also be contained inside a connected evaluation electronic device. If a pressure-measuring cell is in thermal equilibrium with its surroundings, the temperature dependence of the pressure measurement can be well compensated for by means of such a temperature sensor and a suitable processing of the measurement signal. However, temperature jumps can lead to significant measuring errors, which can hardly be compensated for using known methods. Especially in the case of ceramic pressure-measuring cells with a thin measurement membrane having a thickness of, for example, only a few 100 μm, with a medium-exposed surface of approx. 1 cm2 to 10 cm2, the temperature of the measurement membrane quickly follows the temperature of the medium the membrane is exposed to, whereas the heat transfer between the rear face of the counter body and the measurement membrane occurs very slowly, namely, via a circumferential joint between counter body and joint on the outer edge of the measurement membrane and then through the volume of the counter body to its rear face. Thus, a temperature measurement at the rear face of the counter body, in case of doubt, is always delayed.
The published German patent application DE 100 44 078 A1 discloses a pressure-measuring cell with two temperature sensors that are to be arranged at a distance in the direction of the expected temperature gradient. For this reason, the first temperature sensor is arranged at the measurement membrane that forms the front face of the pressure-measuring cell, where it can quickly follow the temperature changes of the medium, whereas the second temperature sensor is arranged at the rear face of the counter body of the pressure measuring cell and facing away from the measurement membrane. The first temperature sensor is arranged at the front face of the counter body, embedded in the joint and contacted via electrical transits through the base body.
A comparison between the temperature signals of both temperature sensors then enables the detection of a temperature gradient and a more accurate compensation of the effects that are caused by the temperature gradient, such as a curvature of the measurement membrane and/or the counter body, or changes in rigidities. The patent application mentions further that the temperature gradient can be established using the time derivative of the signal from the first temperature sensor.
However, as mentioned above, the joint between the measurement membrane and the counter body actually provides a significant thermal resistance, so that an additional temperature sensor at the front face of the counter body is, on the one hand, a significant improvement with regard to prior art; on the other hand, this temperature sensor is also exposed to the thermal influence of the counter body volume, so that, in case of quick temperature jumps, distortion is still to be expected. If a sealing ring is impacting the front face of the measurement membrane in the area of the joint, this can also have an influence on the temperature measurement value of the first temperature sensor, which can impair the temperature compensation.
SUMMARY OF THE INVENTION
Thus, the present invention is based upon the objective of providing a pressure-measuring cell and a method for operating it, wherein the pressure measuring cell provides a further improved temperature compensation.
The objective is achieved by the invention through the pressure measurement cell and the method.
The pressure sensor according to the invention comprises an operating circuit; and a pressure-measuring cell comprising a counter body; a measurement membrane, which is arranged on the counter body and can be deformed by a pressure to be measured; and a capacitive transducer, which has at least one membrane electrode arranged at the measurement membrane and at least one counter-body electrode arranged at the counter body, wherein the capacitance between the membrane electrode and the counter-body electrode depends upon a pressure-dependent deformation of the measurement membrane, wherein at least the membrane electrode has a temperature-dependent impedance; wherein the operating circuit is designed to sense at least one capacitance between the at least one counter-body electrode and the at least one membrane electrode and to provide a pressure measurement value on the basis of at least one capacitance and to determine the impedance of the membrane electrode—particularly, the ohmic portion of the impedance of the membrane electrode.
The temperature dependence of the impedance is, in particular, provided by a temperature-dependent ohmic resistance of the membrane electrode material.
In a further development of the invention, the operating circuit is designed to determine a temperature value for the measurement membrane, depending upon the impedance of the membrane electrode.
In a further development of the invention, the operating circuit is designed, depending upon the impedance of the membrane electrode, to perform a temperature compensation and/or temperature gradient compensation, in order to provide a compensated pressure measurement value.
The pressure sensor according to the invention enables the determination of the measurement membrane temperature, which is generally influenced by the entire surface of the measurement membrane, and not only by the edge region, in which the measurement membrane is coupled with other heat sources or heat sinks, which distort the temperature measurement, thus providing an insufficient basis for a temperature compensation.
Furthermore, the pressure sensor according to the invention—unlike the prior art—does not require any additional connections or transits through the counter body for determining the temperature of the measurement membrane. Thus, the determination of the membrane temperature is cost-neutral as far as the design is concerned.
In a further development of the invention, the operating circuit is designed to determine the impedance of the membrane electrode using a time constant of a charge and/or discharge process of the capacitance between the membrane electrode and the at least one counter body electrode.
In a further development of the invention, the operating circuit, along with the capacitance between the membrane electrode and the at least one counter body electrode, forms an oscillating circuit, wherein the operating circuit is designed to determine the impedance of the membrane electrode using a characteristic value of the oscillating circuit, e.g., a phase angle between a charging voltage and a charging current in the oscillating circuit, or using the quality or the damping of the oscillating circuit.
In a further development of the invention, the impedance of the membrane electrode depends not only upon the temperature but also upon a deformation of the measurement membrane, wherein the operating circuit is designed, depending upon the at least one capacitance between the membrane electrode and the at least one counter body electrode, to determine the deformation influence upon the impedance of the membrane electrode, and to compensate for it during the determination of a temperature value of the measurement membrane, wherein the temperature value determined in this way is to be used for performing a temperature compensation and/or temperature gradient compensation during the determination of the pressure measurement value.
In a further development of the invention, the membrane electrode features a semiconductor—in particular, a metal oxide—especially, titanium dioxide.
In a further development of the invention, the pressure sensor further comprises a second temperature sensor, which is arranged on a rear face of the counter body facing away from the measurement membrane, wherein the operating circuit is designed to perform a temperature compensation or a temperature gradient compensation depending upon a temperature of the measurement membrane determined by way of the impedance of the measurement membrane and using a temperature measurement value of the second temperature sensor.
In a further development of the invention, the measurement membrane is joined with the counter body by way of a circumferential electroconductive joint in a pressure-tight manner, wherein the joint comprises, in particular, an active hard solder, and wherein the membrane electrode is connected to the joint in an electroconductive manner.
In a further development of the invention, the capacitive transducer has a differential capacitor with a first counter body electrode and a second counter body electrode, wherein the first counter body electrode is surrounded by the second counter body electrode in a circular manner, and wherein the first capacitance between the first counter body electrode and the membrane electrode equals a second capacitance between the second counter body electrode and the membrane electrode, when the measurement membrane and the counter body are in their rest positions.
The method according to the invention for determining a pressure measurement value by means of a pressure sensor, which pressure sensor has a capacitive transducer for converting a pressure-dependent deformation of a measurement membrane into an electrical signal, wherein the pressure sensor comprises cross-sensitivities regarding the temperature of the measurement membrane and/or regarding the temperature gradient between the measurement membrane and further components of the pressure sensor, wherein the capacitive transducer has a membrane electrode with a temperature-dependent impedance, is a method that comprises the following steps: Determining a deformation-dependent capacitance measurement value of the capacitive transducer; determining a temperature-dependent impedance measurement value of the membrane electrode; and determining a temperature-compensated and/or temperature gradient-compensated pressure measurement value dependent upon the capacitance measurement value and the impedance measurement value.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in the following in further detail on the basis of the exemplary embodiments shown in the figures. Illustrated are:
FIG. 1: a longitudinal view through an exemplary embodiment of a pressure-measuring cell according to the invention.
FIG. 2: a diagram that depicts the loss angle tan (delta) as a function at various temperatures of the pressure; and
FIG. 3. a diagram that depicts discharge curves of a capacitor at various electrode temperatures.
 DETAILED DISCUSSION IN CONJUNCTION WITH THE DRAWINGS
The pressure-measuring cell 1 shown in FIG. 1 comprises a disk-shaped, ceramic measurement membrane 2 that is in a pressure-tight connection along a circumferential joint 4 with a much stiffer disk-shaped ceramic counter body 3, thus creating a measuring chamber 5 between the counter body 3 and the measurement membrane 2. The measurement membrane and the counter body may comprise, in particular, corundum. The joint may comprise, in particular, an active hard solder, for example, a Zr—Ni—Ti active hard solder.
The measuring membrane 2 has a membrane electrode 7 across its entire counter body surface that includes a metal oxide—especially, a doped metal oxide—for example, titanium dioxide doped with Nb or W, wherein the electrode has a diameter of 2 R, with R being the radius of the flexible area of the measuring diaphragm that corresponds to the internal radius of the joint. On the surface of the counter body on the side of the measurement membrane, a central, disk-shaped measuring electrode 8 is arranged that is contacted by a disk-shaped reference electrode 9 which is mainly of the same capacity as the diaphragm electrode 7 in the rest position of the measurement membrane 2. The distance of the reference electrode 9 to the measuring electrode 8 and the joint 4 is about 0.1 R each. The reference electrode 9 and the measuring electrode 8 are in electrical contact via metallic transits 10, 11 through the base body. The membrane electrode 7 may, for example, be placed on switching ground via the joint.
For determining a pressure measurement value, the capacitances between the measurement electrode 8 and the membrane electrode 7, on the one hand, and the reference electrode 9 and the membrane electrode 7, on the other hand, are captured. The determination of a pressure measurement value by means of these capacitances is generally known, and described in, for example, the published German patent application, DE 10 2011 078 557 A1.
The electrode material of the membrane electrode 7 has a temperature-dependent resistance, which provides the opportunity for determining the temperature of the measurement membrane 2, and, based upon that, for performing a temperature compensation or a temperature gradient compensation. For this, different approaches are described below.
Basically, the capacitances between the counter body electrode and the membrane electrode of the pressure-measuring cell can be viewed as capacitances of an oscillating circuit, wherein the ohmic resistances in such an oscillating circuit can be determined by the tangent of the loss angle tan (δ), wherein the loss angle δ corresponds to the difference between 90° and the phase angle ϕ between current and voltage. For the pressure-measuring cell of the pressure sensor according to the invention, the determining ohmic resistance is provided by the membrane electrode 7 and ranges over a typical operating temperature range, depending upon doping, between, for example, 1 and 8 kΩ. As shown in FIG. 2, the values for the tangent of the loss angle show a readily measurable temperature dependence, so that, after a determination of the loss angle, whose pressure-dependence still has to be corrected by means of the measured capacitances, the temperature of the measurement membrane 2 can be determined to a sufficiently accurate degree, as to therewith enable a temperature compensation to be performed. For determining the loss angle, an oscillating circuit, which contains the measuring capacitance, needs to be operated preferably at its resonance frequency, which resonance frequency can, for example, be determined by means of a frequency sweep with a given excitation voltage.
In practice, capacitive pressure-measuring cells are often operated by charging pumps or so-called switched capacitor circuits, wherein, for example, a precision capacitor, whose capacitance is to be determined, is charged with a defined voltage, wherein the precision capacitor is subsequently discharged into an evaluation capacitor, wherein the resulting voltage of the evaluation capacitor is a measure for the sought capacitance. Of course, this applies only if enough time is left for the charging and discharging processes. In reality, current operating circuits are designed such that enough time is provided for the capacitances to charge and discharge, which, in the case of small capacitances, often takes no longer than a few microseconds, or even less than 1 μs.
As shown in FIG. 3, the temperature-dependent resistance of the membrane electrode also has an influence on the discharge time of a capacitor, which contains the membrane electrode. This provides the opportunity, by means of a sequence of charging and discharging processes—during which the capacitances of the membrane electrode are respectively charged and discharged over different times t1, t2, and t3—to determine a time constant and by said time constant to determine a temperature value for the measurement membranes. Based upon this, a temperature compensation or a temperature gradient compensation during the determination of a pressure measurement value can be performed.
For a temperature compensation, on the one hand, only one temperature value for the measurement membrane temperature can be used, which value is determined using the method described above, while, on the other hand, a second temperature sensor (not shown in FIG. 1) can additionally be used, which temperature sensor is arranged on the rear face of the counter body of the pressure-measuring cell. By comparing the temperature values of the measurement membrane and of the rear face of the counter body, an additional temperature gradient compensation is possible. A significant indication for a temperature gradient can also be obtained from the time derivative of the temperature of the measurement membranes.
The operating circuit can, in particular, be realized in the form of an ASIC, which is arranged on the rear face of the pressure-measuring cell. Furthermore, such an ASIC can also be only a partial component of the operating circuit, which ASIC, in particular, communicates with a main processor, which analyses the signals provided by the ASIC for performing a temperature compensation or temperature gradient compensation during determination of a pressure measurement value.

Claims (10)

The invention claimed is:
1. A pressure sensor, comprising:
an operating circuit; and
a pressure-measuring cell with a counter body; a measurement membrane, which is arranged on said counter body and is deformable by a pressure to be measured; and a capacitive transducer, which has at least one membrane electrode that is arranged at said measurement membrane and at least one counter body electrode that is arranged at said counter body, wherein the capacitance between said at least one membrane electrode and said counter body electrode depends upon a pressure-dependent deformation of said measurement membrane, wherein said at least one membrane electrode has a temperature-dependent impedance, wherein:
said operating circuit is designed to capture at least one capacitance between said at least one counter body electrode and said at least one membrane electrode, and to provide a pressure measurement value in dependence upon the at least one capacitance, as well as to determine the impedance of said at least one membrane electrode—particularly, the ohmic portion of said at least one impedance of the membrane electrode.
2. The pressure sensor according to claim 1, wherein:
said operating circuit is designed, depending upon the impedance of said at least one membrane electrode, to perform a temperature compensation and/or temperature gradient compensation, in order to provide a compensated pressure measurement value.
3. The pressure sensor according to claim 1, wherein:
said operating circuit is designed to determine the impedance of said at least one membrane electrode using a time constant of a charge and/or discharge process of the capacitance between said at least one membrane electrode and said at least one counter body electrode.
4. The pressure sensor according to claim 1, wherein:
said operating circuit, along with the capacitance between membrane electrode and at least one counter body electrode, forms an oscillating circuit;
said operating circuit is designed to determine the impedance of membrane electrode using a characteristic value of said oscillating circuit, e.g., a phase angle between a charging voltage and a charging current in oscillating circuit, or using the quality or the damping of oscillating circuit.
5. The pressure sensor according to claim 1, wherein:
the impedance of said at least one membrane electrode depends not only upon the temperature but also upon a deformation of said measurement membrane;
said operating circuit is designed, depending upon the at least one capacitance between said at least one membrane electrode and said at least one counter body electrode, to determine the deformation influence on the impedance of said at least one membrane electrode, and to compensate for it during the determination of a temperature value of said measurement membrane; and
the temperature value determined in this way is to be used for performing a temperature compensation and/or temperature gradient compensation during the determination of the pressure measurement value.
6. The pressure sensor according to claim 1, wherein:
said at least one membrane electrode has a semiconductor—in particular, a metal oxide—especially, a titanium dioxide or a doped titanium oxide—for example, titanium oxide doped with Nb or W.
7. The pressure sensor according to claim 1, further comprising:
a second temperature sensor, which is arranged on a rear face of said counter body facing away from said measurement membrane, wherein:
said operating circuit is designed to perform a temperature compensation or a temperature gradient compensation depending upon a temperature of said measurement membrane determined by way of the impedance of said measurement membrane and using a temperature measurement value of said second temperature sensor.
8. The pressure sensor according to claim 1, wherein:
said measurement membrane is joined with said counter body by way of a circumferential electroconductive joint in a pressure-tight manner;
the joint comprises, in particular, an active hard solder; and
said at least one membrane electrode is connected to the joint in an electroconductive manner.
9. The pressure sensor according to claim 1, wherein:
said capacitive transducer has a differential capacitor with a first counter body electrode and a second counter body electrode;
said first counter body electrode is surrounded by said second counter body electrode in a circular manner; and
said first capacitance between said first counter body electrode and said at least one membrane electrode equals a second capacitance between said second counter body electrode and said at least one membrane electrode, when said measurement membrane and said counter body are in their rest positions.
10. A method for determining a pressure measurement value by means of a pressure sensor—particularly, by means of a pressure sensor according to claim 1, which pressure sensor has a capacitive transducer for converting a pressure-dependent deformation of a measurement membrane into an electrical signal, wherein:
the pressure sensor comprises cross-sensitivities regarding the temperature of the measurement membrane and/or regarding the temperature gradient between the measurement membrane and further components of the pressure sensor;
the capacitive transducer has a membrane electrode with a temperature-dependent impedance, wherein the method comprises the following steps:
determining a deformation-dependent capacitance measurement value of the capacitive transducer;
determining a temperature-dependent impedance measurement value of the membrane electrode; and
determining a temperature-compensated and/or temperature gradient-compensated pressure measurement value dependent upon the capacitance measurement value and the impedance measurement value.
US15/104,008 2013-12-20 2014-11-14 Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method Active 2035-01-26 US9976923B2 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
DE102013114734.8 2013-12-20
DE102013114734.8A DE102013114734A1 (en) 2013-12-20 2013-12-20 Capacitive pressure cell with at least one temperature sensor and pressure measuring method
DE102013114734 2013-12-20
PCT/EP2014/074656 WO2015090771A1 (en) 2013-12-20 2014-11-14 Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method

Publications (2)

Publication Number Publication Date
US20160320256A1 US20160320256A1 (en) 2016-11-03
US9976923B2 true US9976923B2 (en) 2018-05-22

Family

ID=51900446

Family Applications (1)

Application Number Title Priority Date Filing Date
US15/104,008 Active 2035-01-26 US9976923B2 (en) 2013-12-20 2014-11-14 Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method

Country Status (5)

Country Link
US (1) US9976923B2 (en)
EP (1) EP3094951B1 (en)
CN (1) CN105917204B (en)
DE (1) DE102013114734A1 (en)
WO (1) WO2015090771A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180038754A1 (en) * 2016-08-05 2018-02-08 Encite Llc Micro Pressure Sensor

Families Citing this family (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013113843A1 (en) * 2013-12-11 2015-06-11 Endress + Hauser Gmbh + Co. Kg pressure sensor
DE102015105057A1 (en) 2015-04-01 2016-10-06 Endress + Hauser Gmbh + Co. Kg Capacitive pressure sensor
EP3124937B1 (en) * 2015-07-29 2018-05-02 VEGA Grieshaber KG Method for determining a pressure and measuring assembly for same
DE102015122220A1 (en) 2015-12-18 2017-06-22 Endress + Hauser Gmbh + Co. Kg Ceramic pressure measuring cell with at least one temperature transducer and pressure transducer with such a pressure measuring cell
DE102016104760A1 (en) * 2015-12-22 2017-06-22 Endress + Hauser Gmbh + Co. Kg Pressure measuring device
US10129676B2 (en) * 2016-02-16 2018-11-13 Infineon Technologies Ag MEMS microphone, apparatus comprising a MEMS microphone and method for fabricating a MEMS microphone
DE102016105001A1 (en) 2016-03-17 2017-09-21 Endress + Hauser Gmbh + Co. Kg Pressure measuring device
EP3232174B1 (en) * 2016-04-11 2018-10-31 VEGA Grieshaber KG Pressure sensor
EP3232173B1 (en) * 2016-04-11 2018-09-26 VEGA Grieshaber KG Differential pressure sensor
CA3021078C (en) 2016-04-11 2024-02-13 The Alfred E. Mann Foundation For Scientific Research Pressure sensors with tensioned membranes
DE102016112352A1 (en) * 2016-07-06 2018-01-11 Endress+Hauser Gmbh+Co. Kg Differential pressure sensor for determining a pressure measuring signal
DE102017130393A1 (en) * 2017-12-18 2019-06-19 Endress+Hauser SE+Co. KG Method for operating a pressure sensor
DE102017131066A1 (en) * 2017-12-22 2019-06-27 Endress+Hauser SE+Co. KG Method of providing calibrated pressure transducers
DE102018106563B4 (en) * 2018-03-20 2019-11-14 Vega Grieshaber Kg Method for measured value compensation for capacitive pressure cells
US11402289B2 (en) * 2018-03-20 2022-08-02 Vega Grieshaber Kg Means for implementing a method for detecting and compensating for a rapid temperature change in a pressure measuring cell
US11027967B2 (en) * 2018-04-09 2021-06-08 Invensense, Inc. Deformable membrane and a compensating structure thereof
US11225409B2 (en) 2018-09-17 2022-01-18 Invensense, Inc. Sensor with integrated heater
FR3098769B1 (en) * 2019-07-15 2022-10-07 Faurecia Sieges Dautomobile VEHICLE SEAT WITH COMPENSATION SYSTEM
JP2022541901A (en) * 2019-07-17 2022-09-28 ユーイー ライフサイエンシズ インコーポレイティド Systems and methods for measuring tissue parameters using capacitive tactile sensors
DE102019133325A1 (en) * 2019-12-06 2021-06-10 Endress+Hauser SE+Co. KG Pressure transducer
JP7662406B2 (en) 2021-05-17 2025-04-15 アズビル株式会社 Diaphragm Vacuum Gauge

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4011901A1 (en) 1990-04-12 1991-10-17 Vdo Schindling Capacitive pressure sensor with simultaneous temp. measurement - contains plates carrying electrodes, one carrying temp. dependent resistance path
DE4111118A1 (en) 1991-04-03 1992-10-08 Univ Chemnitz Tech Micro-mechanical capacitative pressure transducer - has diaphragm spring with frame coupled to movable electrode plate ia diaphragm
EP1174696A2 (en) 2000-07-20 2002-01-23 VEGA Grieshaber KG Pressure measurement cell with temperature sensor
EP1186875A2 (en) 2000-09-07 2002-03-13 Vega Grieshaber KG Pressure measurement cell with temperature sensors and method for measuring pressure
US6532824B1 (en) * 1999-07-09 2003-03-18 Tokin Corporation Capacitive strain sensor and method for using the same
DE102005008959A1 (en) 2005-02-28 2006-09-07 Plöchinger, Heinz, Dipl.-Ing. Pressure sensor for vacuum applications, has similar diaphragms connected together with electromechanical transducer converting deflection to electrical signal
DE102009002662A1 (en) 2009-04-27 2010-10-28 Ifm Electronic Gmbh Capacitive pressure sensor, particularly combination sensor for detecting measuring parameter, has ceramic pressure measuring cell which consists of diaphragm, base body and measuring electrodes in form of conductive surface areas
US20110308320A1 (en) 2010-06-21 2011-12-22 Robert Bosch Gmbh Inductively Coupled Pressure Sensor
EP2520917A1 (en) 2011-05-04 2012-11-07 Nxp B.V. MEMS Capacitive Pressure Sensor, Operating Method and Manufacturing Method
US20130336095A1 (en) * 2010-12-20 2013-12-19 Teknologian Tutkimuskeskus Vtt Sensor and a sensor system
US20140053651A1 (en) * 2012-08-23 2014-02-27 Willem Frederik Adrianus Besling Pressure sensor

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN87209178U (en) * 1987-06-17 1987-12-30 天津大学 High temp.-resistant and vibration-proof capacitance pressure transducer
US6698294B2 (en) * 2000-09-07 2004-03-02 Vega Grieshaber Kg Pressure cell with temperature sensors and pressure measuring method
CN100420021C (en) * 2005-04-07 2008-09-17 中国科学院电子学研究所 Monolithic integrated temperature, humidity and pressure sensor chip based on polymer materials
CN1975358A (en) * 2006-12-14 2007-06-06 中国航天科技集团公司第六研究院第十一研究所 Low-temperature film pressure sensor and producing method thereof
CN201707167U (en) * 2010-05-18 2011-01-12 北京遥测技术研究所 Ultralow-temperature diaphragm pressure/temperature compound sensor
DE102011078557A1 (en) 2011-07-01 2013-01-03 Endress + Hauser Gmbh + Co. Kg Method for operating an absolute or relative pressure sensor with a capacitive transducer

Patent Citations (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4011901A1 (en) 1990-04-12 1991-10-17 Vdo Schindling Capacitive pressure sensor with simultaneous temp. measurement - contains plates carrying electrodes, one carrying temp. dependent resistance path
DE4111118A1 (en) 1991-04-03 1992-10-08 Univ Chemnitz Tech Micro-mechanical capacitative pressure transducer - has diaphragm spring with frame coupled to movable electrode plate ia diaphragm
US6532824B1 (en) * 1999-07-09 2003-03-18 Tokin Corporation Capacitive strain sensor and method for using the same
EP1174696A2 (en) 2000-07-20 2002-01-23 VEGA Grieshaber KG Pressure measurement cell with temperature sensor
EP1186875A2 (en) 2000-09-07 2002-03-13 Vega Grieshaber KG Pressure measurement cell with temperature sensors and method for measuring pressure
DE10044078A1 (en) 2000-09-07 2002-04-04 Grieshaber Vega Kg Pressure measuring cell with temperature sensors and pressure measuring method
DE102005008959A1 (en) 2005-02-28 2006-09-07 Plöchinger, Heinz, Dipl.-Ing. Pressure sensor for vacuum applications, has similar diaphragms connected together with electromechanical transducer converting deflection to electrical signal
DE102009002662A1 (en) 2009-04-27 2010-10-28 Ifm Electronic Gmbh Capacitive pressure sensor, particularly combination sensor for detecting measuring parameter, has ceramic pressure measuring cell which consists of diaphragm, base body and measuring electrodes in form of conductive surface areas
US20110308320A1 (en) 2010-06-21 2011-12-22 Robert Bosch Gmbh Inductively Coupled Pressure Sensor
US20130336095A1 (en) * 2010-12-20 2013-12-19 Teknologian Tutkimuskeskus Vtt Sensor and a sensor system
EP2520917A1 (en) 2011-05-04 2012-11-07 Nxp B.V. MEMS Capacitive Pressure Sensor, Operating Method and Manufacturing Method
US20130118265A1 (en) * 2011-05-04 2013-05-16 Nxp B.V. Mems capacitive pressure sensor, operating method and manufacturing method
US9383282B2 (en) 2011-05-04 2016-07-05 Ams International Ag MEMS capacitive pressure sensor, operating method and manufacturing method
US20140053651A1 (en) * 2012-08-23 2014-02-27 Willem Frederik Adrianus Besling Pressure sensor

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
English Translation of the International Preliminary Report on Patentability, WIPO, Geneva, CH, Jun. 30, 2016.
German Search Report, German Patent Office, Munch, DE, Mar. 26, 2014.
International Search Report, EPO, The Netherlands, Feb. 5, 2015.

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180038754A1 (en) * 2016-08-05 2018-02-08 Encite Llc Micro Pressure Sensor
US11454563B2 (en) * 2016-08-05 2022-09-27 Encite Llc Micro pressure sensor

Also Published As

Publication number Publication date
EP3094951A1 (en) 2016-11-23
EP3094951B1 (en) 2020-10-28
CN105917204A (en) 2016-08-31
DE102013114734A1 (en) 2015-07-09
US20160320256A1 (en) 2016-11-03
CN105917204B (en) 2019-08-27
WO2015090771A1 (en) 2015-06-25

Similar Documents

Publication Publication Date Title
US9976923B2 (en) Capacitive pressure-measuring cell having at least one temperature sensor and pressure measurement method
TWI618922B (en) Method and arrangement for measuring vacuum pressure with a measurement cell arrangement
US10883892B2 (en) Ceramic pressure measurement cell having at least one temperature transducer and pressure sensor having a pressure measurement cell of this type
US7841239B2 (en) Electrostatic capacitance diaphragm vacuum gauge and vacuum processing apparatus
CN103748447B (en) A kind of operation has the absolute pressure of capacitive pick-up or the method for relative pressure sensor
US7325457B2 (en) Sensor and sensor module
US6698294B2 (en) Pressure cell with temperature sensors and pressure measuring method
US20150096388A1 (en) Pressure sensor
CN110307930B (en) Method for detecting and compensating for rapid temperature changes in a pressure measuring device
US9689766B2 (en) Pressure sensor with cover layer
CN104062060A (en) Double-range silicon piezoresistive type pressure sensitive element
CN110319971B (en) Measuring circuit for measuring pressure in bipolar capacitance type vacuum gauge
US7219551B2 (en) Differential pressure sensor
CN108700479A (en) Capacitive vacuum measuring cell with multiple electrodes
EP1914531B1 (en) Deformation detection sensor
RU2537517C1 (en) Semiconductor pressure transducer
US10436660B2 (en) Pressure transducer and method for operating same
US11976994B2 (en) Sensor for detecting pressure, filling level, density, temperature, mass and/or flow rate including nanowires arranged on coupling section
CN112432721B (en) Pressure sensor fault detection circuit, method and pressure sensor
US11402289B2 (en) Means for implementing a method for detecting and compensating for a rapid temperature change in a pressure measuring cell
CN210464785U (en) Bipolar capacitance type vacuum gauge and corresponding measuring circuit thereof
JP7662406B2 (en) Diaphragm Vacuum Gauge
Kärkkäinen et al. New MEMS pressure sensor element and concept for coronary catheter
US11248975B2 (en) High dynamic range capacitive pressure sensor
CN117346945A (en) Measuring device and method for operating a measuring device

Legal Events

Date Code Title Description
AS Assignment

Owner name: ENDRESS + HAUSER GMBH + CO. KG, GERMANY

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BURGARD, MARTIN;DREWES, ULFERT;PONATH, NILS;AND OTHERS;SIGNING DATES FROM 20160421 TO 20160502;REEL/FRAME:038895/0406

STCF Information on status: patent grant

Free format text: PATENTED CASE

AS Assignment

Owner name: ENDRESS+HAUSER SE+CO.KG, GERMANY

Free format text: CHANGE OF NAME;ASSIGNOR:ENDRESS+HAUSER GMBH+CO. KG;REEL/FRAME:046443/0294

Effective date: 20180514

MAFP Maintenance fee payment

Free format text: PAYMENT OF MAINTENANCE FEE, 4TH YEAR, LARGE ENTITY (ORIGINAL EVENT CODE: M1551); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

Year of fee payment: 4

点击 这是indexloc提供的php浏览器服务，不要输入任何密码和下载